Motor

ABSTRACT

The present invention aims at providing a motor which can stably be mounted on a circuit board when being assembled into an instrument in particular. The motor  1  in accordance with the present invention comprises a motor body A, an output shaft  3  projecting from a front end of the motor body A, and a voltage-supplying terminal  8  provided in the motor body A, the terminal  8  having an elastic force in a direction substantially orthogonal to the output shaft  3  and also having a grounding portion  14  disposed near a rear end of the motor body A.

TECHNICAL FIELD

The present invention relates to a motor; and, in particular, to asmall-size motor which is built into a portable communicationsinstrument (e.g., cellular phone) and is utilized as a source forgenerating vibrations for calling functions.

BACKGROUND ART

Conventionally known as techniques in such a field are those disclosedin Japanese Utility Model Publication No. SHO 62-23248 and JapanesePatent Application Laid-Open No. HEI 11-136901. The former publicationproposes a technique in which, while a motor contact for supplyingcurrent to a motor brush has a flexibility, its elastic repulsive forceis actively utilized. On the other hand, a small-Size motor 100disclosed in the latter publication is made such that it is easilyassembled into communications instruments such as a cellular phone. Asshown in FIG. 6, the small-size motor 100 has an output shaft 103 towhich a weight 104 is secured, whereas a forwardly extending electricterminal 102 is fixed at a barrel 100 a of the small-size motor 100 byway of a bracket 105 and a holder 109. If such an electric terminal 102made of a spring sheet is utilized, then no soldering is necessary whensecuring the motor 100 onto a circuit board 101, whereby the efficiencyof production improves.

DISCLOSURE OF THE INVENTION

However, the above-mentioned conventional motors have a problem asfollows. Namely, since the electric terminal 102 obliquely extendsforward, the front end of the terminal 102 is grounded on the circuitboard 101, whereby the motor 100 would be placed on the circuit board101 in an unstable state in terms of its weight balance. In cases wherethe motor is built into other instruments such as a cellular phone inparticular, it is necessary for a lid of the cellular phone or the liketo press the motor 100 from thereabove. If its assembling operation iscarried out in the unstable state shown in FIG. 6, however, then themotor 100 may move leftward in the drawing due to the pressure from theupper side (see the depicted arrow), whereby the terminal 102 may bedetached from its predetermined electric contact 101 a on the circuitboard 101. That is, the motor 100 has a problem that it is not easilyassembled into other instruments.

In order to overcome the above-mentioned problem, it is an object of thepresent invention to provide a motor which can stably be mounted on acircuit board when being assembled into an instrument in particular.

The motor in accordance with the present invention comprises a motorbody, an output shaft projecting from a front end of the motor body, anda voltage-supplying terminal provided in the motor body, the terminalhaving an elastic force in a direction substantially orthogonal to theoutput shaft and also having a grounding portion disposed near a rearend of the motor body.

At the time of assembling a motor, the present invention intends toplace the motor on a circuit board such that the grounding portion ofits terminal comes into electric contact with a predetermined positionon the circuit board. Namely, since the terminal has an elastic force,it is necessary for the motor to be stable on the circuit board whenplaced thereon. In the motor in accordance with the present invention,the grounding portion of the terminal is disposed near the rear end ofthe motor body so as to face the output shaft, whereby the motor attainsa supporting balance on the circuit board, thus improving its stability.Also, from the viewpoint of keeping the rotational balance of the outputshaft itself, which rotates at a high speed in front of the motor, it isquite meaningful to dispose the grounding portion of the terminal nearthe rear end of the motor body.

Preferably, in the above-mentioned motor, the terminal is formed bybending an elastic material and comprises a first portion extendingsubstantially parallel to the output shaft from the motor body; a secondportion extending substantially parallel to the first portion from afront end of the first portion by way of a bent part; and a thirdportion, formed with the grounding portion, projecting outward in acurved manner from a rear end of the second portion. When such aconfiguration is employed, the terminal can be formed with a simplestructure at a low cost, whereby its cost of manufacture can be cutdown.

Preferably, the above-mentioned motor further comprises a weighteccentrically secured to the output shaft. When such a configuration isemployed, a vibrating motor can be constructed appropriately, whereby itbecomes easier to assemble the motor into communications instrumentssuch as a cellular phone.

The present invention will be more fully understood from the detaileddescription given hereinbelow and the accompanying drawings, which aregiven byway of illustration only and are not to be considered aslimiting the present invention.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will beapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing an embodiment of the motor in accordancewith the present invention;

FIG. 2 is a bottom view of the motor shown in FIG. 1;

FIG. 3 is a front view of the motor shown in FIG. 1;

FIG. 4 is a rear view of the motor shown in FIG. 1;

FIG. 5 is a perspective view showing a terminal employed in the motor ofthe present invention; and

FIG. 6 is a side view showing a conventional motor.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, a preferred embodiment of the motor in accordance withthe present invention will be explained in detail with reference to thedrawings.

As shown in FIGS. 1 to 4, a motor 1 comprises a cored motor, therebyattaining a smaller size. The motor 1 comprises a motor body A having ametal-made motor case (barrel) 2 with a diameter of about 4 mm and alength of about 10 mm. Secured to the inner wall face of the motor case2 is a stator made of a permanent magnet having N and S poles. The motorcase 2 contains therein a rotor comprising an iron core wound with acoil. Secured to the center of the rotor is an output shaft 3 supportedwith a bearing. The output shaft 3 extends such that its leading endportion penetrates through the front end portion of the motor case 2.

Secured to the rear end of the output shaft 3 is a commutator with whicha pair of brushes are slidably in contact. Secured to each brush is aplanar contact 4, whereas the rear end of each contact 4 projects from abracket 5 secured to the rear end of the motor case 2. Also, a weight 6having substantially a semicylindrical form is cramped onto orpress-fitted into the leading end portion of the output shaft 3, so asto be eccentrically secured to the output shaft 3. As the eccentricallysecured weight 6 rotates along with the rotation of the output shaft 3,the motor case 2 can be vibrated. Such a weight-equipped motor 1 isutilized for notifying a user of incoming calls in a pager, a cellularphone, or the like.

Here, the motor body A is provided with two terminals 8 for allowing thecontacts 4 and their corresponding predetermined electric contacts in acircuit board 7 to electrically connect with each other upon a singlemotion. The terminals 8 are used for applying a predetermined externalvoltage to the brushes, and are disposed so as to correspond to theirrespective contacts 4. The base end of each terminal 8 is secured to itscorresponding contact 4 with solder S. The terminal 8 is formed from athin spring sheet, whereby the terminal 8 itself is provided withelasticity.

The terminal 8 is formed by bending a thin spring. As shown in FIGS. 1and 5, the terminal 9 has an attachment 10 to be secured to itscorresponding contact 4 of the motor body A with the solder S, whereasthe attachment 10 radially extends along an end face of the bracket 5.Further, the terminal 8 has a first portion 11 bent inward (toward theweight 6) at right angles at the lower end of the attachment 10. Thefirst portion 11 extends substantially parallel to the output shaft 3along the peripheral face of the motor case 2.

Also, the terminal 8 has a second portion 12 which extends substantiallyparallel to the first portion 11 by way of a bent part B at which thefront end of the first portion 11 is bent into a U-shape. The secondportion 12 extends up to about a half of the first portion 11. Theterminal 8 has a third portion 13 which is bent so as to project outwardfrom the rear end of the second portion 12. Further, the rear end of thethird portion 13 is formed with a curved part 13 a having a top areaformed with a grounding portion 14 whose surface is plated with Au. Thegrounding portion 14 ensures electric connection between the terminal 8and its corresponding predetermined electric contact in the circuitboard 7. Employing the terminal 8 thus formed by bending a spring sheetenables the terminal to be formed with a simple structure at a low cost,whereby the cost of manufacture would eventually be cut down.

Also, the terminal 8 is contained in a slit 17 a of a leg 17 disposednear the rear end of the motor case 2 (see FIG. 2). Here, the thirdportion 13 of the terminal 8 is exposed from the slit 17 a. As aconsequence, without exposing the whole terminal 8, which is likely tobe damaged, the part necessary for electric junction can be inspectedvisually, whereby the motor 1 can easily be assembled into otherinstruments.

Due to the foregoing configuration, the terminal 8 has a resilient forcein a direction substantially orthogonal to the output shaft 3, while thegrounding portion 14 of the terminal 8 is disposed on the motor case 2(barrel) side of the motor body A near the rear end thereof.

Consequently, as shown in FIG. 1, such an assembling operation ispossible in which, while the motor 1 is disposed on the circuit board 7and held in this state, a lid of an unshown instrument or the likepresses the motor 1 from thereabove in the direction of arrow Z. In thiscase, the terminal 8 elastically deforms as indicated by thedash-double-dot line in FIG. 1, so as to be pressed against the circuitboard 7, whereby the grounding portion 14 of the terminal 8 and itscorresponding electric contact are reliably connected to each other.

Also, when the motor 1 is placed on the circuit board 7 upon assemblingthe motor 1 into an instrument such as a cellular phone, the terminal 8deforms, due to the weight of motor 1 and the weight 6, such that thethird portion 13 approaches the first portion 11. Thus, if the groundingportion 14 of the terminal 8 is disposed near the rear end of the motorbody A so as to face the output shaft 3, the supporting balance of themotor 1 on the circuit board 7 can be made better, whereby the stabilityof the motor 1 becomes quite favorable. Also, from the view point ofkeeping the rotational balance of the output shaft 3 itself, whichrotates at a high speed in front of the motor 1, it is quite meaningfulto dispose the grounding portion 14 of the terminal 8 near the rear endof the motor body A.

On the other hand, the motor body A is covered with a rubber-made holder16 as indicated by the dash-double-dot lines in FIGS. 2 and 3.Consequently, when the motor 1 vibrates along with the rotation of theweight 6, unnecessary vibrating sounds wound not occur from the housingof the instrument. Here, the third portion 13 of the terminal 8 isexposed to the outside by way of a slit-like groove 16 a formed in theholder 16.

Since the motor in accordance with the present invention is configuredas in the foregoing, it attains effects as follows. Namely, since themotor comprises a motor body, an output shaft projecting from a frontend of the motor body, and a voltage-supplying terminal provided in themotor body, whereas the terminal has an elastic force in a directionsubstantially orthogonal to the output shaft and also has a groundingportion disposed near a rear end of the motor body, the motor can stablybe mounted on a circuit board when being assembled into an instrument.

Industrial Applicability

From the invention thus described, it will be obvious that the inventionmay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedfor inclusion within the scope of the following claims.

18. A communications instrument comprising: a printed circuit boardhaving an electrical contact; a lid positioned over the printed circuitboard; a vibrating motor assembly press fit between the lid and theprinted circuit board, the vibrating motor assembly including a motorbody, an output shaft and a terminal, the terminal including a contactportion positioned generally to the side of the mirror body near a rearend of the motor body that is opposite the front end of the motor body,the contact portion f the terminal engaging the electrical contact onthe printed circuit board and apply an elastic force against theelectrical contact.
 19. A communications instrument according to claim18, wherein the elastic force applied by the contact portion of theterminal is substantially perpendicular to the output shaft.
 20. Acommunications instrument according to claim 18, wherein thecommunication instrument is a cellular phone.
 21. A communicationsinstrument according to claim 18, wherein the communications instrumentis a pager.